The global warming debate on Capitol Hill is heating up. Government scientists refused to comply with lawmakers’ demands they turn over internal documents regarding a study that eliminated the “hiatus” in global warming from the temperature record.

National Oceanic and Atmospheric Administration (NOAA) officials argued such records are confidential and “essential to frank discourse among scientists.” The science agency said it has a history of protecting the “confidentiality of deliberative scientific discussions.”

NOAA’s decision not to comply with a subpoena from House science committee lawmakers has only angered Chairman Lamar Smith , a Texas Republican, who says Americans have a right to know what taxpayer-funded scientists were thinking when they altered the temperature record in June.

“It was inconvenient for this administration that climate data has clearly showed no warming for the past two decades,” Smith said in an emailed statement. “The American people have every right to be suspicious when NOAA alters data to get the politically correct results they want and then refuses to reveal how those decisions were made.”

Republican lawmakers have been interested in holding hearings and gathering information on NOAA temperature adjustments for months. Lawmakers’ interests peaked when scientists put out a study claiming the 15-year “hiatus” in global warming never existed.

“Newly corrected and updated global surface temperature data from NOAA’s [National Centers for Environmental Information] do not support the notion of a global warming ‘hiatus,’” NOAA scientists led by Tom Karl wrote in their study.

Karl and his team made adjustments to past temperature data to eliminate a prolonged period of little to no statistically significant global warming. They largely did this by adjusting upward sea surface temperature readings taken from ships and buoys.

The NOAA study was highly criticized by scientists more skeptical of man-made global warming and directly contradicts findings by the Intergovernmental Panel on Climate Change, the world’s main authority on global warming. Many scientists are still skeptical of NOAA’s elimination of the pause.

What concerned Smith and other lawmakers about the data adjustments was the timing. They were just two months before President Barack Obama unveiled sweeping Environmental Protection Agency regulations limiting carbon dioxide emissions from power plants.

The adjusted NOAA data also came about six months ahead of when United Nations delegates are set to meet in Paris to hash out a global agreement to cut CO2 emissions. Obama has made signing such an agreement a main part of his presidential legacy. The White House would no doubt welcome data showing more global warming in the past 15 years.

“NOAA needs to come clean about why they altered the data to get the results they needed to advance this administration’s extreme climate change agenda,” Smith said. “The agency has yet to identify any legal basis for withholding these documents.”

Smith has been especially frustrated by NOAA because the science agency ignored three attempts by lawmakers to get internal communications before he was forced to issue a subpoena for the data. NOAA did provide Smith with scientific data and methodology regarding the June study — most of which is publicly available.

“We stand behind our scientists, who conduct their work in an objective manner,” a NOAA spokeswoman told Nature. “We have provided all of the information the Committee needs to understand this issue.”

“The Committee intends to use all tools at its disposal to undertake its Constitutionally-mandated oversight responsibilities,” Smith said.

Smith’s actions, however, have been heavily criticized by Democrats and liberal media outlets.

The liberal explanatory journalism site Vox ran the headline “The House science committee is worse than the Benghazi committee” in reaction to Smith’s subpoena.

“With the science committee, it is working scientists being intimidated, who often do not have the resources to defend themselves, and the threat is to the integrity of the scientific process in the US,” according to Vox. “It won’t take much for scientists to get the message that research into politically contested topics is more hassle than it’s worth.”

Interestingly enough, there was no outrage on the left when Democratic lawmakers were demanding documents from university climate scientists and organizations who disagreed with the Obama administration’s position on global warming.